The present application relates to a semiconductor integrated circuit device which is effective for use in a microprocessor comprising a plurality of memories. Moreover, the present invention relates to a semiconductor integrated circuit device forming a plurality of function cells, each of having a unit function module, on a semiconductor substrate and a testing configuration which is capable of testing each function cell in a microcomputer system.
A semiconductor integrated circuit device of the function cell system (hereinafter referred to as LSI) forming a microcomputer system, which usually mounts a processor and a variety of peripheral circuits on a printed circuit board on one semiconductor substrate, is described in the "LSI Handbook", p. 478, issued on Nov. 30, 1984 by OHM Co., Ltd. In such LSI, unit function blocks such as processors, memories, input/output port and peripheral controllers (CRT controller, communication INTERFACE controller, etc.) are considered standard function cell. These blocks are integrated on one semiconductor substrate to form an LSI as a system.
In such LSI of the function cell system, various function cells are coupled as specified through the wiring regions in accordance with the functions required by the LSI in question.
In the LSI of function cell system explained above, all signal input/output functions of the function cells comprised therein are not required to be used by the external circuits. For instance, it is usually unnecessary to provide, for the external circuit, the control signal which is used only for control of internal circuits of the LSI.
Therefore, in the case of testing an LSI formed by the function cell system, it is possible that the AC parameter test or function test of each function cell comprised therein cannot be conducted individually or easily from the external circuit. In this case, an individual test program for each function cell cannot be used. A composite test, such as an indirect function cell test, must be conducted through mutual operations of function cells. Consequently, problems such as lowering of test efficiency and reliability are generated.
A one chip microprocessor is also proposed. In this case, a microprogram system forming a processor and a peripheral circuit on one semiconductor substrate is employed. A microprocessor of this type provides a plurality of memories such as an instruction ROM (Read Only Memory), which stores microinstructions or instructions, and a data buffer RAM (Random Access Memory), which temporarily stores calculation data, etc.